Effects of Flow-Diverting Device Oversizing on Hemodynamics Alteration in Cerebral Aneurysms

Abstract

BACKGROUND AND PURPOSE: Flow-diverting devices are increasingly being considered for large or giant aneurysms with wide necks, which are difficult to treat with coils or clips. These devices are often oversized to achieve good positioning against the artery wall. The objective of this study was to analyze the effect of oversized flow-diverting devices in altering aneurysmal flows and creating hemodynamic environments favorable for thrombosis and aneurysm occlusion.

Enhanced Aneurysmal Flow Diversion Using a Dynamic Push-Pull Technique: An Experimental and Modeling Study

“…However, these 2 were typical cases suitable for flow diversion (wide necks and complex geometries less optimal for coiling or clipping); 2) the 3.5 ϫ 20 mm FD for high-compaction was oversized (3.5 versus 3 mm) due to limited FD sample availability. Oversized FDs were reported to achieve less flow reduction than nonoversized ones, 13 indicating an underestimation to the flow reduction of the current high-compaction scenario; and 3) rigid wall was assumed through the deployment. Future direction would be to further examine the effects of DPPT on aneurysm occlusion and perforator preservation in clinical cases following flow diversion.…”

Optic chiasm compression from mass effect and thrombus formation following unsuccessful treatment of a giant supraclinoid ICA aneurysm with the Pipeline device: open surgical bailout with STA-MCA bypass and parent vessel occlusion

“…There is ongoing research in flow dynamics relating to flow diverters, but this represents an understudied field of research. 10,11 One such study demonstrated that even reductions in flow velocity do not significantly reduce intraaneurysmal pressure. 12 As those who have placed these devices have seen, there is great variability in how quickly aneurysm obliteration occurs.…”

Virtual-versus-Real Implantation of Flow Diverters: Clinical Potential and Influence of Vascular Geometry

“…Finally, our method also provides crucial information such as the filament location and neck porosity for further hemodynamic evaluation with computational fluid dynamics simulations. [13][14][15][16] …”

“…11,12 The device sizing impacting the stent porosity was shown to influence the intra-aneurysmal flow modification. 13 Currently, there is no clinical tool to predict these stent properties accurately and provide clinical insight to the practitioner. Furthermore, hemodynamic simulations have shown high potential in predicting intracranial aneurysm thrombosis.…”

“…Therefore, we have recently proposed 17 a virtual stent-deployment method able to predict the local properties of braided stents (wire location, angles, porosities) and implantation parameters (stent length, landing zone) with minimal computational cost. Contrary to other methods that involve either cumbersome finite element analysis [18][19][20][21] or complex phenomenologic constraints 13,20,[22][23][24][25][26] to simulate the stent dynamics, the proposed model is based on a minimal number of geometric assumptions (ie, a constant interwire distance and tubular stent envelope), which were validated in vitro and in vivo for the Pipeline Embolization Device (PED; Covidien, Irvine, California).…”